Plants grow more than 160 billion tons of cellulose—the material that makes up the walls of plant cells—every year, but only a tiny fraction of that is useful to humans in the crops we grow. This is frustrating, as cellulose is made up of glucose chains that are almost, but not quite, the same as those that make up the starch that constitutes 20 to 40 percent of most peoples' daily calorie intake.

With the world's population forecast to reach nine billion by 2050, working out how to alter cellulose glucose into something more practical could be vital for preventing starvation. There's also an extra benefit in that some could be used for biofuels.

Biological systems engineers from Virginia Polytechnic Institute and State University investigated ways of breaking cellulose down into more basic glucose blocks, and how to combine them back together into more complex starches. To do this, the team needed enzymes generated by a genetically modified E.coli bacteria (the genes were taken from fungi, potatoes and other bacteria).

That gave the team a collection of enzymes. The first breaks cellulose down into the slightly simpler cellobiose, which another enzyme then splits into two individual glucose molecules—one on its own, the other with one phosphate molecule attached. That phosphate molecule allows the glucose to combine together into amylose, a starch powder that's edible but not digestible. It is present in many foods, is a good source of fiber, and has been shown to improve the digestive health of people who eat it regularly.

It also has other practical uses. The study's coauthor, Percival Zhang, said: "Besides serving as a food source, the starch can be used in the manufacture of edible, clear films for biodegradable food packaging. It can even serve as a high-density hydrogen storage carrier that could solve problems related to hydrogen storage and distribution."

The process renders a third of cellulose into edible starch, with the other two-thirds rendered into a useable biofuel—none of the cellulose is wasted. For every ton of grain harvested by farmers, there can be two or three times as much plant material discarded, and that "grain stover" is what was used in this research. However, future research could mean that cellulose found in other plants that are not considered edible at all, such as trees, might prove to have a use.

However, it is unclear how economical this process is. Zhang told Science that it could cost roughly $1 million to turn 200kg of cellulose into 20kg of starch, which is a lot of money for what is apparently only enough for one person across 80 days. Further research will be needed to see if the process has a commercial future.

27 Reader Comments

Sensationalist title aside, there is no real shortage of starch or glucose. Or to be more precise, there is no shortage of nutrition-less carbohydrate calories, especially in developed countries and underdeveloped countries where we are already using the crop and composting or refining what is left. Many food issues in countries that cannot seem to shed starvation have to do with poor infrastructure and distribution in response to food shortages, and high food prices. Or disruption of native growing of food crop because foreign countries give you food for free to inflate prices in their own countries (artificial food shortages to protect home turf farmers), making farming unprofitable, and lease your arable land for growing biofuels *cough*.

What normally happens to the plant matter that this processes uses? Is it the chaff that is normally returned to the ground? What happens when it's not? Are we pulling even more nutrients out of the ground?

"Today, we produce about four billion metric tonnes of food per annum. Yet due to poor practices in harvesting, storage and transportation, as well as market and consumer wastage, it is estimated that 30–50% (or 1.2–2 billion tonnes) of all food produced never reaches a human stomach. Furthermore, this figure does not reflect the fact that large amounts of land, energy, fertilisers and water have also been lost in the production of foodstuffs which simply end up as waste."

Yumm ... predigested food. I don't understand why we didn't just have cows chew the cud for us.

By the way, if you see cellulose on the nutrition label, it meas they've been putting that inedible saw dust in your meal already to give it some consistency. It's already been in our food as a source of fiber.

What normally happens to the plant matter that this processes uses? Is it the chaff that is normally returned to the ground? What happens when it's not? Are we pulling even more nutrients out of the ground?

The same can be said of cemetaries. If you lock all the dead bodies away in caskets, you're not returning the nutrients back to the soil.

Didn't really have much else to add, just felt like chiming that little bit in.

We can already produce bio-fuels en masse. What we're lacking is large production of cheap, healthy protein. Humans can't exist on glucose alone. Insects can convert plants into protein, they breed like wild fire, and are very bioassimilable and provide large amounts of essential fatty acids along with chitinous fiber (that absorbs saturated fat, too).

Third world countries will probably be where insect farming en masse gets pioneered. First worlders turn up their noses. You take a place with lots of farm land ... instead of raising goats or cows ... harvest the crops then toss all the inedible parts onto a grub farm pile for meal worms or something. Let them go crazy, breed, then harvest the adult meal worms to convert into protein paste. Find ways to sneak that into inexpensive recipes and protein / meal replacement bars ... you can feed tons of folks inexpensively.

By contrast, folks like Monsanto say Soy Beans are the protein of the future. Of course they would claim that, b/c they have the market cornered on that. But, soy protein sucks compared to insect protein. Even animal protein sucks, b/c insect protein is more assimilable. Since soy beans are less costly to produce (no maintenance to clean out grub pens and such), of course they want to push their "solution" as the wave of the future. But, it would be interesting if folks figured out that by comparison, soy beans suck and insects are amazing.

Please, stop with the "agricultural waste" thing already, crop residue is essential to maintain or improve organic (as in carbon-based, not organic farming) matter content in the soil, reduce chemical fertilizer use, reduce erosion and reduce the effect of droughts. There is no such thing as agricultural waste for crops, crop residue is gold to the farmer.

This starch process is an economical and environmental aberration. For each truck of, say corn grain, you'd need like 3 trucks of stover, and special machines to compress it, bale it, collect it into trucks, compacting the soil in the process, transport it into the processing plant, process it, dry the waste, collect the waste into trucks again, transport it back to the farm, use special equipment to spread the waste back into the field where it came from, also compacting the soil in the process. And you can probably spread only half or a fifth of the field anyway because the starch extraction process removed all the cellulose cells, so much of the organic matter benefit of the original crop residue is gone. So is the erosion prevention benefit, as crop residue form a mat of fibers over the soil, whereas the waste is probably more like a powder or a sludge with all structural fibers broken down.

I'd be surprised if the energy and economical balance sheet is one tenth of the effort you poured into the whole process from start to end. These guys also talk about mobile processing plants that you could just transport to the farm or field, but it would still remove most of the organic matter content from the crop residue and return to the soil very little of what it took from it. All that to make more industrial dirt cheap starch which is used to make HFCS, junk food and (very inefficiently) ethanol. Do we really need more of it?

What normally happens to the plant matter that this processes uses? Is it the chaff that is normally returned to the ground? What happens when it's not? Are we pulling even more nutrients out of the ground?

Yes, which is then restored with materials such as potash. The increased need for potash would then stimulate potash mines (yes it is mined) and the US has potash mines so it's good for the economy once again!

What normally happens to the plant matter that this processes uses? Is it the chaff that is normally returned to the ground? What happens when it's not? Are we pulling even more nutrients out of the ground?

The same can be said of cemetaries. If you lock all the dead bodies away in caskets, you're not returning the nutrients back to the soil.

Didn't really have much else to add, just felt like chiming that little bit in.

You actually do, albeit indirectly.

Insects and large bacteria start decomposing your body the moment you die. Sometimes even before. Then, smaller bacteria digest or decompose dead bacteria. Depending on many factors such as climate, your intestinal flora, the casket material and the place you are buried, bacteria can process your tissues fairly quickly. These bacteria die or are ingested by other bacteria. The process keeps going for weeks or months till the vast majority of molecules that were once part of your body have been returned to the soil.

I have no idea how the cycle works in cemeteries where they stack dead bodies in niches. They seal the niche so I don't know. I'd guess there're trillions of dead bacteria after the decomposing (?)

"Today, we produce about four billion metric tonnes of food per annum. Yet due to poor practices in harvesting, storage and transportation, as well as market and consumer wastage, it is estimated that 30–50% (or 1.2–2 billion tonnes) of all food produced never reaches a human stomach. Furthermore, this figure does not reflect the fact that large amounts of land, energy, fertilisers and water have also been lost in the production of foodstuffs which simply end up as waste."

What normally happens to the plant matter that this processes uses? Is it the chaff that is normally returned to the ground? What happens when it's not? Are we pulling even more nutrients out of the ground?

The same can be said of cemetaries. If you lock all the dead bodies away in caskets, you're not returning the nutrients back to the soil.

Didn't really have much else to add, just felt like chiming that little bit in.

You actually do, albeit indirectly.

Insects and large bacteria start decomposing your body the moment you die. Sometimes even before. Then, smaller bacteria digest or decompose dead bacteria. Depending on many factors such as climate, your intestinal flora, the casket material and the place you are buried, bacteria can process your tissues fairly quickly. These bacteria die or are ingested by other bacteria. The process keeps going for weeks or months till the vast majority of molecules that were once part of your body have been returned to the soil.

I have no idea how the cycle works in cemeteries where they stack dead bodies in niches. They seal the niche so I don't know. I'd guess there're trillions of dead bacteria after the decomposing (?)

If it's a casket only, then yes. But, funeral homes have gotten into the habit of suckering folks into also paying for a burial vault. A large cement box the casket goes in. On the one hand, it can keep the ground from caving in when if it was a casket only decomposing. On the other hand... I don't think anything can "leak" outside of that cement vault. The funeral home gets paid extra for the vault, so they're big on pushing it.

Had a gf that worked at a large funeral home / cemetary, and I ride by it on the way to work every day. It just seems like a waste. Just plant people bare in the ground, and after 5 years, till it up and use it as farm land. Rotate the land between burial and farm land. We're all just walking fertilizer waiting to happen. Gf said there was starting to be a movement for "natural cemetaries" that do that. They cover you in muslin and plant you in the ground. Never heard of any near me, though.

What normally happens to the plant matter that this processes uses? Is it the chaff that is normally returned to the ground? What happens when it's not? Are we pulling even more nutrients out of the ground?

The same can be said of cemetaries. If you lock all the dead bodies away in caskets, you're not returning the nutrients back to the soil.

Didn't really have much else to add, just felt like chiming that little bit in.

You actually do, albeit indirectly.

Insects and large bacteria start decomposing your body the moment you die. Sometimes even before. Then, smaller bacteria digest or decompose dead bacteria. Depending on many factors such as climate, your intestinal flora, the casket material and the place you are buried, bacteria can process your tissues fairly quickly. These bacteria die or are ingested by other bacteria. The process keeps going for weeks or months till the vast majority of molecules that were once part of your body have been returned to the soil.

I have no idea how the cycle works in cemeteries where they stack dead bodies in niches. They seal the niche so I don't know. I'd guess there're trillions of dead bacteria after the decomposing (?)

If it's a casket only, then yes. But, funeral homes have gotten into the habit of suckering folks into also paying for a burial vault. A large cement box the casket goes in. On the one hand, it can keep the ground from caving in when if it was a casket only decomposing. On the other hand... I don't think anything can "leak" outside of that cement vault. The funeral home gets paid extra for the vault, so they're big on pushing it.

Had a gf that worked at a large funeral home / cemetary, and I ride by it on the way to work every day. It just seems like a waste. Just plant people bare in the ground, and after 5 years, till it up and use it as farm land. Rotate the land between burial and farm land. We're all just walking fertilizer waiting to happen. Gf said there was starting to be a movement for "natural cemetaries" that do that. They cover you in muslin and plant you in the ground. Never heard of any near me, though.

Worse, most bodies are stll embalmed to delay the natural process, so folks can walk by an look at what used to be you. Then they seal the vastly expensive hermetically sealed metal casket (more $$$$$) and bury that in the vault (more $$$$ as you said).

A good friend passed away last year, he was cremated and his widow spread the ashes in Yosemite (not really allowed to do that, but if no one sees you.........).

What normally happens to the plant matter that this processes uses? Is it the chaff that is normally returned to the ground? What happens when it's not? Are we pulling even more nutrients out of the ground?

The same can be said of cemetaries. If you lock all the dead bodies away in caskets, you're not returning the nutrients back to the soil.

Didn't really have much else to add, just felt like chiming that little bit in.

You actually do, albeit indirectly.

Insects and large bacteria start decomposing your body the moment you die. Sometimes even before. Then, smaller bacteria digest or decompose dead bacteria. Depending on many factors such as climate, your intestinal flora, the casket material and the place you are buried, bacteria can process your tissues fairly quickly. These bacteria die or are ingested by other bacteria. The process keeps going for weeks or months till the vast majority of molecules that were once part of your body have been returned to the soil.

I have no idea how the cycle works in cemeteries where they stack dead bodies in niches. They seal the niche so I don't know. I'd guess there're trillions of dead bacteria after the decomposing (?)

If it's a casket only, then yes. But, funeral homes have gotten into the habit of suckering folks into also paying for a burial vault. A large cement box the casket goes in. On the one hand, it can keep the ground from caving in when if it was a casket only decomposing. On the other hand... I don't think anything can "leak" outside of that cement vault. The funeral home gets paid extra for the vault, so they're big on pushing it.

Had a gf that worked at a large funeral home / cemetary, and I ride by it on the way to work every day. It just seems like a waste. Just plant people bare in the ground, and after 5 years, till it up and use it as farm land. Rotate the land between burial and farm land. We're all just walking fertilizer waiting to happen. Gf said there was starting to be a movement for "natural cemetaries" that do that. They cover you in muslin and plant you in the ground. Never heard of any near me, though.

Worse, most bodies are stll embalmed to delay the natural process, so folks can walk by an look at what used to be you. Then they seal the vastly expensive hermetically sealed metal casket (more $$$$$) and bury that in the vault (more $$$$ as you said).

A good friend passed away last year, he was cremated and his widow spread the ashes in Yosemite (not really allowed to do that, but if no one sees you.........).

Worse than all of that, at least were i live, the undertakers have managed to lobby for various laws to protect their profit margins so its illegal to build your own simple pine coffin, you have to buy a "professionally" made one the cheapest one being well into four digits. When my father was cremated we got his remains in a gold wrapping paper covered cardboard box, which is now illegal, my more recently cremated relative had to be in a 600$ plastic urn ... Literally a cheap plastic bucket if used for anything other than ashes.

This enzyme plan to make even more "useless" biomass useful to humans would result in even less biomass and nutrients being cycled back into the soil, wouldn't it? It sounds like a recipe for greatly accelerated soil depletion.

What normally happens to the plant matter that this processes uses? Is it the chaff that is normally returned to the ground? What happens when it's not? Are we pulling even more nutrients out of the ground?

The same can be said of cemetaries. If you lock all the dead bodies away in caskets, you're not returning the nutrients back to the soil.

Didn't really have much else to add, just felt like chiming that little bit in.

You actually do, albeit indirectly.

Insects and large bacteria start decomposing your body the moment you die. Sometimes even before. Then, smaller bacteria digest or decompose dead bacteria. Depending on many factors such as climate, your intestinal flora, the casket material and the place you are buried, bacteria can process your tissues fairly quickly. These bacteria die or are ingested by other bacteria. The process keeps going for weeks or months till the vast majority of molecules that were once part of your body have been returned to the soil.

I have no idea how the cycle works in cemeteries where they stack dead bodies in niches. They seal the niche so I don't know. I'd guess there're trillions of dead bacteria after the decomposing (?)

If it's a casket only, then yes. But, funeral homes have gotten into the habit of suckering folks into also paying for a burial vault. A large cement box the casket goes in. On the one hand, it can keep the ground from caving in when if it was a casket only decomposing. On the other hand... I don't think anything can "leak" outside of that cement vault. The funeral home gets paid extra for the vault, so they're big on pushing it.

Had a gf that worked at a large funeral home / cemetary, and I ride by it on the way to work every day. It just seems like a waste. Just plant people bare in the ground, and after 5 years, till it up and use it as farm land. Rotate the land between burial and farm land. We're all just walking fertilizer waiting to happen. Gf said there was starting to be a movement for "natural cemetaries" that do that. They cover you in muslin and plant you in the ground. Never heard of any near me, though.

Worse, most bodies are stll embalmed to delay the natural process, so folks can walk by an look at what used to be you. Then they seal the vastly expensive hermetically sealed metal casket (more $$$$$) and bury that in the vault (more $$$$ as you said).

A good friend passed away last year, he was cremated and his widow spread the ashes in Yosemite (not really allowed to do that, but if no one sees you.........).

Worse than all of that, at least were i live, the undertakers have managed to lobby for various laws to protect their profit margins so its illegal to build your own simple pine coffin, you have to buy a "professionally" made one the cheapest one being well into four digits. When my father was cremated we got his remains in a gold wrapping paper covered cardboard box, which is now illegal, my more recently cremated relative had to be in a 600$ plastic urn ... Literally a cheap plastic bucket if used for anything other than ashes.

Yep. They will think of anything to squeeze your wallet long after you're dead.

Yep. They will think of anything to squeeze your wallet long after you're dead.[/quote]

I have a standing deal with my family and friends, when i die have a decent party with whatever cash i have left and whatever you can get for my few belongings. Then, at about 3 am, strip my body of any identification, stick a dirty hypodermic in my arm and throw me in the the dumpster in the back alley. Let me find peace amongst the rats, roaches, and pigeons

Awesome possibilities. Just somebody please think to make sure some released reproduction-optimized gene-engineered fungo-bacterium (it takes only one) doesn't turn every plant in the world to goo in a few months. Please.

"What normally happens to the plant matter that this processes uses? Is it the chaff that is normally returned to the ground? What happens when it's not? Are we pulling even more nutrients out of the ground?"

If the conditions are anaerobic, the decomposition process results in a significant release of Methane: a Carbon Dioxide Equivalent with a Global Warming Potential of 25 over 100 years.

What normally happens to the plant matter that this processes uses? Is it the chaff that is normally returned to the ground? What happens when it's not? Are we pulling even more nutrients out of the ground?

Yes, but (there's always a but...)

This process allows us to use the carbohydrates (made from atmospheric CO2 and H2O) that we previously couldn't use. There's no reason the minerals and nitrogen couldn't be returned to the soil.

Would you really want all that calcium, magnesium, etc. dissolved in your fuel? Obviously not, as it would tend to accumulate and clog things up when the fuel is burned.

Worse than all of that, at least were i live, the undertakers have managed to lobby for various laws to protect their profit margins so its illegal to build your own simple pine coffin, you have to buy a "professionally" made one the cheapest one being well into four digits. When my father was cremated we got his remains in a gold wrapping paper covered cardboard box, which is now illegal, my more recently cremated relative had to be in a 600$ plastic urn ... Literally a cheap plastic bucket if used for anything other than ashes.

Wow, that's pretty damn cynical. Did they give any reason for those laws that could conceivably have been of any benefit to the customer, as opposed to simply lining their own pockets? It would be nice to think they at least tried to make it sound legit, rather than just a cash grab. How on earth did the legislators find something like that a good idea?

A family friend died suddenly recently, and the arrangements his family made brought to my attention a rather lovely way of being laid to rest that I think I'd like for myself when the time comes (long may it be till that day): Meadow burial

Yep. They will think of anything to squeeze your wallet long after you're dead.[/quote]

I have a standing deal with my family and friends, when i die have a decent party with whatever cash i have left and whatever you can get for my few belongings. Then, at about 3 am, strip my body of any identification, stick a dirty hypodermic in my arm and throw me in the the dumpster in the back alley. Let me find peace amongst the rats, roaches, and pigeons[/quote]

That's illegal and a health hazard. Only a good idea if you're hoping to get your family and friends arrested.